Take advantage of CodeActionLiteral client capability

If client advertises `CodeActionLiteralSupport`, using that for
`java.apply.workspaceEdit` would allow clients to use a generic
algorithm, instead of being forced to provide a special case for jdt.ls.

Fixes #376

Signed-off-by: Boris Staletic <boris.staletic@gmail.com>

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/handlers/CodeActionHandler.java

@@ -173,10 +173,13 @@ private Optional<Either<Command, CodeAction>> getCodeActionFromProposal(ChangeCo
 		}
 
 		if (preferenceManager.getClientPreferences().isSupportedCodeActionKind(proposal.getKind())) {
-			// TODO: Should set WorkspaceEdit directly instead of Command
 			CodeAction codeAction = new CodeAction(name);
 			codeAction.setKind(proposal.getKind());
-			codeAction.setCommand(command);
+			if (preferenceManager.getClientPreferences().isSupportedCodeActionLiteral()) {
+				codeAction.setEdit((WorkspaceEdit)command.getArguments().get(0));
+			} else {
+				codeAction.setCommand(command);
+			}
 			codeAction.setDiagnostics(context.getDiagnostics());
 			return Optional.of(Either.forRight(codeAction));
 		} else {

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/preferences/ClientPreferences.java

@@ -261,8 +261,20 @@ public boolean isSemanticHighlightingSupported() {
 
 	/**
 	 * {@code true} if the client has explicitly set the
-	 * {@code textDocument.documentSymbol.hierarchicalDocumentSymbolSupport} to
-	 * {@code true} when initializing the LS. Otherwise, {@code false}.
+	 * {@code textDocument.codeAction.codeActionLiteralSupport}
+	 * when initializing the LS. Otherwise, {@code false}.
+	 */
+	public boolean isSupportedCodeActionLiteral() {
+		//@formatter:off
+		return v3supported && capabilities.getTextDocument().getCodeAction() != null
+				&& capabilities.getTextDocument().getCodeAction().getCodeActionLiteralSupport() != null;
+		//@formatter:on
+	}
+
+	/**
+	 * {@code true} if the client has listed {@code kind} in
+	 * {@code textDocument.codeAction.codeActionLiteralSupport.codeActionKind.valueSet}
+	 * when initializing the LS. Otherwise, {@code false}.
 	 */
 	public boolean isSupportedCodeActionKind(String kind) {
 		//@formatter:off

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/text/correction/SourceAssistProcessor.java

@@ -352,7 +352,11 @@ private Optional<Either<Command, CodeAction>> convertToWorkspaceEditAction(CodeA
 		if (preferenceManager.getClientPreferences().isSupportedCodeActionKind(kind)) {
 			CodeAction codeAction = new CodeAction(name);
 			codeAction.setKind(kind);
-			codeAction.setCommand(command);
+			if (preferenceManager.getClientPreferences().isSupportedCodeActionLiteral()) {
+				codeAction.setEdit(workspaceEdit);
+			} else {
+				codeAction.setCommand(command);
+			}
 			codeAction.setDiagnostics(context.getDiagnostics());
 			return Optional.of(Either.forRight(codeAction));
 		} else {

org.eclipse.jdt.ls.tests/src/org/eclipse/jdt/ls/core/internal/handlers/CodeActionHandlerTest.java

@@ -51,6 +51,7 @@
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.runners.MockitoJUnitRunner;
+import static org.mockito.Mockito.when;
 
 /**
  * @author Gorkem Ercan
@@ -97,6 +98,32 @@ public void testCodeAction_removeUnusedImport() throws Exception{
 		Assert.assertEquals(CodeActionHandler.COMMAND_ID_APPLY_EDIT, c.getCommand());
 	}
 
+	@Test
+	public void testCodeActionLiteral_removeUnusedImport() throws Exception{
+		when(preferenceManager.getClientPreferences().isSupportedCodeActionLiteral()).thenReturn(true);
+		ICompilationUnit unit = getWorkingCopy(
+				"src/java/Foo.java",
+				"import java.sql.*; \n" +
+						"public class Foo {\n"+
+						"	void foo() {\n"+
+						"	}\n"+
+				"}\n");
+
+		CodeActionParams params = new CodeActionParams();
+		params.setTextDocument(new TextDocumentIdentifier(JDTUtils.toURI(unit)));
+		final Range range = CodeActionUtil.getRange(unit, "java.sql");
+		params.setRange(range);
+		params.setContext(new CodeActionContext(Arrays.asList(getDiagnostic(Integer.toString(IProblem.UnusedImport), range))));
+		List<Either<Command, CodeAction>> codeActions = getCodeActions(params);
+		Assert.assertNotNull(codeActions);
+		Assert.assertTrue(codeActions.size() >= 3);
+		Assert.assertEquals(codeActions.get(0).getRight().getKind(), CodeActionKind.QuickFix);
+		Assert.assertEquals(codeActions.get(1).getRight().getKind(), CodeActionKind.QuickFix);
+		Assert.assertEquals(codeActions.get(2).getRight().getKind(), CodeActionKind.SourceOrganizeImports);
+		WorkspaceEdit w = codeActions.get(0).getRight().getEdit();
+		Assert.assertNotNull(w);
+	}
+
 	@Test
 	public void testCodeAction_sourceActionsOnly() throws Exception {
 		//@formatter:off
@@ -228,6 +255,30 @@ public void testCodeAction_removeUnterminatedString() throws Exception{
 		Assert.assertEquals(CodeActionHandler.COMMAND_ID_APPLY_EDIT, c.getCommand());
 	}
 
+	@Test
+	public void testCodeActionLiteral_removeUnterminatedString() throws Exception{
+		when(preferenceManager.getClientPreferences().isSupportedCodeActionLiteral()).thenReturn(true);
+		ICompilationUnit unit = getWorkingCopy(
+				"src/java/Foo.java",
+				"public class Foo {\n"+
+						"	void foo() {\n"+
+						"String s = \"some str\n" +
+						"	}\n"+
+				"}\n");
+
+		CodeActionParams params = new CodeActionParams();
+		params.setTextDocument(new TextDocumentIdentifier(JDTUtils.toURI(unit)));
+		final Range range = CodeActionUtil.getRange(unit, "some str");
+		params.setRange(range);
+		params.setContext(new CodeActionContext(Arrays.asList(getDiagnostic(Integer.toString(IProblem.UnterminatedString), range))));
+		List<Either<Command, CodeAction>> codeActions = getCodeActions(params);
+		Assert.assertNotNull(codeActions);
+		Assert.assertFalse(codeActions.isEmpty());
+		Assert.assertEquals(codeActions.get(0).getRight().getKind(), CodeActionKind.QuickFix);
+		WorkspaceEdit w = codeActions.get(0).getRight().getEdit();
+		Assert.assertNotNull(w);
+	}
+
 	@Test
 	public void testCodeAction_exception() throws JavaModelException {
 		URI uri = project.getFile("nopackage/Test.java").getRawLocationURI();